Precision Twist Drill 5998109 Jobber Drill Bit 72 Hss

Product Description

The PRECISION TWIST DRILL 5998109 is a jobber-length drill bit in wire gauge size 72, with a decimal diameter of 0.0250 inches. Made from high speed steel with a bright uncoated finish, it features a standard 118-degree split point, a two-flute spiral configuration, and a web-thinned, tapered-web design that reduces thrust and improves chip evacuation. The straight-cylindrical shank measures 0.0250 inches in diameter, and the overall length is 1.125 inches. This bit is sized for precision drilling in small-diameter applications and is suited for use by machinists, maintenance technicians, and trade professionals who require tight tolerances in small-bore work.

The 5998109 is designed for drilling into steel, cast iron, non-ferrous metals, superalloys, and titanium. Its general-purpose grade and regular spiral type make it a practical choice for production drilling, repair work, and toolroom applications. With a flute length of 0.3125 inches and a maximum drilling depth of 0.3125 inches, it is optimized for shallow, precise holes in hard and varied materials. The right-hand cutting direction is standard for conventional drill press and hand-drill use.

Key Features

• Wire gauge size 72, decimal diameter 0.0250 inches for small-bore precision work
• High speed steel construction with bright uncoated finish for general-purpose durability
• 118-degree standard point angle with web-thinned, tapered-web design reduces entry thrust
• Two-flute regular spiral with 13xD flute-to-diameter ratio supports chip removal
• Straight-cylindrical shank compatible with standard drill chucks
• Meets ANSI standards; no coolant-through required for typical applications

Compatibility

Part of the R10H-R18H series. Designed as an OEM-style jobber-length drill bit for use in standard drill chucks accepting a 0.0250-inch straight-cylindrical shank. Compatible workpiece materials include steel, cast iron, non-ferrous metals, superalloys, and titanium per supplier specifications.

Installation Notes

Installation is performed by machinists or maintenance technicians using a drill press, CNC machine, or hand drill with a compatible chuck. Secure the shank fully in the chuck before operation and confirm the workpiece is clamped or fixtured to prevent movement. At this diameter, bit breakage risk increases with side load or misalignment, so center-punching the workpiece before drilling is strongly recommended. Follow applicable shop safety practices and machine guarding requirements during use.